The present invention generally relates to a photographic camera and, more particularly, to a photographic camera operable with a 35 mm cartridge film.
In most conventional 35 mm cameras, a roll of film contained in a cartridge is generally load in the camera first by, after the camera back lid has been opened, placing the film cartridge in the film chamber, then drawing out enough film leader from the film cartridge to cover the distance between the film chamber and the film take-up spool, and finally inserting the film leader into the slot of the film take-up spool while allowing the sprocket holes in the film to be engaged by the teeth of the sprocket wheel. With these types of cameras, it is a usual procedure to close the camera back lid after the film has been advanced a certain distance enough to allow the film leader to be turned around the take-up spool to such an extent that a photographer can ascertain that the film leader will no longer disengage from the take-up spool.
However, it has often been observed that most photographers, particularly beginner and armature photographers, are apt to be annoyed about whether or not the film leader has no doubt been engaged, i.e., anchored, to the take-up spool and that some sensitive photographers are apt to allow the film to be advanced a somewhat excessive distance onto the take-up spool to make sure before the camera back lid is closed. Where the film is advanced such excessive distance onto the film take-up spool only to make it sure that the film leader has no doubt been anchored to the take-up spool while the camera back lid has not yet been closed, a few available imaging areas on the film immediately followed by the film leader tend to turn out a failure by exposure to the ambient light, thereby reducing the total number of available imaging areas or frames on the film.
In the case where the photographic cameras are so designed as to be operable with a roll of film of a type wherein a code region H, such as shown in FIG. 2 of the accompanying drawings and including digitally coded areas IH, AH, CH, DH and EH, provided in the film leader along one longitudinal edge thereof for identifying respective photographic characteristics of the film, there is the possibility that some pieces of information coded on the code region H will not be read out by the camera in the event that the film leader is excessively advanced while the camera back lid is opened. In addition to the code perforations in the code region, the film has at least one row of regularly spaced sprocket holes defined therein over the entire length thereof, which sprocket holes may be used to detect the amount of film transported from the film chamber onto the take-up spool by counting the number of sprocket holes passed. One or both of the information contained in the code region and the information given by the sprocket holes can be effectively read out generally if the film is continuously moved, and accordingly, in the case where the manual film winding operation is intermittently carried out as is often observed, the result of the information read-out tends to be confused if the movement of the film is interrupted halfway. Moreover, the continued supply of an electrical power to the information read-out means while the film is not moved results in the waste of the limited electrical power available from a battery source.